Herbs twining. Stems terete, sparsely villous. Petiole 3-5 cm, sparsely villous; leaf blade trullate-lanceolate, ovate-lanceolate, or lanceolate, 12-22 × 2.5-4.5 cm, papery, both surfaces sparsely pubescent or abaxially glabrescent, veins palmate, 7-10 pairs from base, base auriculate, sinus 1-2 cm deep, apex long acuminate. Flowers in axils of leafy shoots, solitary. Pedicel pendulous, 5-7 cm, sparsely villous; bractlets ovate, ca. 3 × 2 mm, inserted on basal 1/2 of peduncle. Calyx tube geniculately curved, abaxially sparsely villous; basal portion of tube ca. 20 × 8 mm; limb cylindric ca. 2 × 0.2-0.3 mm, lobes 3, lanceolate-acuminate, 5-7 × 2-3 mm. Anthers oblong, 1.5-2 mm. Gynostemium 3-lobed. Capsule cylindric, 5-7 × 2-3 cm, dehiscing basipetally. Seeds triangular, ca. 6 × 4 mm. Fl. May-Jun.

Forests; 800-2400 m. Guangxi, Guizhou, Yunnan [Myanmar].